Question

Degree of unsaturation in the empirical formula $C_4{H}_{8}O$ is:

Answer 1

Degree of unsaturation:
$\frac{(2n_c+2)-n_H}{2}=\frac{10-8}{2}=1^o$
$1^o$ D.U. suggests either unsaturated alcohol or cyclic $3^o$ alcohol four C atoms; $3^o$ alcohol cannot be unsaturated, so it is cyclic.